directly develops from receives synaptic input in region sends synaptic output to region LN Pdf neuron s-LNv Pdf neuron M pacemaker M cell morning cell morning neuron small Pdf neuron sLNv PDF fly_anatomy.ontology M oscillator VFB:FBbt_00003764 Dorsal projections judged by curator to terminate in the superior lateral protocerebrum (SLP) as defined by the Ito et al. (2014) standard. This is the only group of pacemaker neurons currently classed as 'morning cells' (Liang et al., 2016; Liang et al., 2017; Delventhal et al., 2019). In some older papers, it is unclear whether l-LNvs are included as 'morning cells' (Grima et al., 2004 - FBrf0179741; Lear et al., 2009 - FBrf0208444). FBbt:00003764 small pigment-dispersing hormone-immunoreactive neuron close to medulla Adult s-LNv neuron that expresses Pdf (FBgn0023178). There are four of these in each ventral cluster of LNs. Short, fine fibers lacking presynaptic sites contact the accessory medulla, whilst longer processes project toward the dorsal protocerebrum and terminate dorsofrontal to the mushroom body calyx close to the pars lateralis and close to the DN2 neurons (Helfrich-Forster et al., 2007). Thes dorsal arbors contain both pre- and postsynaptic connections, including reciprocal connections to DN1p neurons (Yasuyama and Meinertzhagen, 2010, Fernandez et al., 2020), and their morphology and connectivity vary throughout the day (Gorostiza et al., 2014). Pdf rich dense-synaptic vesicles accumulate in terminal varicosities in these cells, but are not associated with presynaptic sites (Miskiewicz et al., 2004; Yasuyama and Meinertzhagen, 2010). They can be observed docked at the plasma membrane, suggesting paracrine release of Pdf. They drive the morning locomotor activity peak (Liang et al., 2016; Liang et al., 2017; Delventhal et al., 2019) and display a morning neural activity peak that precedes this increased locomotor activity (Liang et al., 2016). morning oscillator neuron superior lateral protocerebrum adult s-LNv neuron anterior ectoderm derivative adult visual projection neuron pupal s-LNv Pdf neuron